Ways to preserve ideas

How could one ways to preserve ideas one would want to convey to a future civilization, so that such future civilization could benefit from them (thx, TD May11)?

• Possibilities would be "word of mouth" or "example" - but only in a civilization that lasts itself and is infinitely resilient.

How could you transmit information for a restart?

• As Stephen Hawking suggested in his TED Talk in 2008, create back-up by spreading into space. Moon or Mars would do for most threats. Then after collapse someone can come back and reinfect the new civilization on the old planet with the ideas (and hope these ideas were not responsible for the collapse)

• The KAO project of Jean-Marc Philippe suggests to strore information in a satellite that will come back to earth in 50.000 years to disclose information to the inhabitants then (seems not to have "taken off" yet)

• At Zukunft25 there was a proposal in 2007 for a "million year project" of storage of information for a million years. One suggestion was to collaborate with the nuclear industry and store information along with nuclear waste.

• The nuclear industry has the task of preventing contact with nuclear waste for long periods. The documentation "Into Eternity" about the Finnish site Onkalo suggested that conveying information across such time periods was difficult and that hiding the site in the hope that it will not be discovered - though against current legal requirements - could be the best bet.

• ...